Scielo RSS <![CDATA[Journal of Energy in Southern Africa]]> vol. 25 num. 1 lang. en <![CDATA[SciELO Logo]]> <![CDATA[<b>An indicative assessment of investment opportunities in the African electricity supply sector</b>]]> In the coming decades, demand for electricity will increase considerably on the African continent. Investment in power generation, transmission and distribution is necessary to meet this demand. In this paper a cost-optimization tool is used to assess investment opportunities under varying scenarios of GDP growth, electricity trade and CO2 taxation. Business as usual fuel price outlooks are assumed, and related assumptions are relatively conservative. The goal is to find if there are economic indications that renewable energy might play a significant role in the expansion of the African electricity system. The results show that there is potential of renewable energy (RE) resources to have a significant share in the generation mix. By 2030, 42% and 55% of the total generation is powered by renewables in the high and low GDP scenarios respectively. Promotion of interregional trade can assist in unlocking RE potential across the continent, such as hydro in Central Africa and wind in East Africa; these regions are projected to be net exporters of electricity. Additionally, generation by off-grid technologies increases over time, reaching 12% of the total generation by 2030 in Sub-Saharan Africa. <![CDATA[<b>Impact of thermoelectric cooling modules on the efficiency of a single-phase asynchronous machine</b>]]> In this paper, the authors present the impact of thermoelectric cooling modules (TECMs) on the efficiency of a single-phase asynchronous machine. TECMs are used to lower the stator winding temperature and core temperature of the single-phase asynchronous machine. A similar effect might be possible by operating the asynchronous machine in a controlled lower temperature environment or by using other means of improved controlled cooling. An overview on the materials and method used during the experimental setup of the single-phase asynchronous machine with the TECMs is provided. Experimental results on the efficiency analysis, temperature analysis and equivalent circuit parameter analysis are provided. It is shown that the efficiency of the single-phase asynchronous machine can be increased by 4.44% when cooled by TECMs <![CDATA[<b>Evaluation of noise levels of two micro-wind turbines using a randomised experiment</b>]]> One of the more contentious environmental concerns of wind turbines is the wind turbine noise. This study assesses the noise impacts of two micro-wind turbines on the environment by comparing the noise generated by these turbines to traditionally accepted surrounding sounds. The sound level data was collected using a randomised experiment and fitted using a general linear model (GLM). The GLM was used to determine the relationship between the sound level generated at a given site to the time of day, the wind speed, the wind direction and a fixed predetermined distance from the sound source <![CDATA[<b>SADC's response to climate change - the role of harmonised law and policy on mitigation in the energy sector</b>]]> The negligible levels of energy-related GHG emissions attributable to the Southern African sub-region translates into the sub-region contributing relatively little towards global climate change. Notwithstanding, the member states comprising the Southern African Development Community (SADC) are among the most vulnerable to the trans boundary effects of global climate change. Existing SADC climate change policy documents highlight the important role of the energy sector in climate change mitigation. Furthermore, various international, African Union and SADC legal instruments stress the crucial role of harmonised law and policy as climate change adaptive measure. It is the central hypothesis of this paper that harmonised sub-regional law and policy aimed at regulating SADC member states' mitigation efforts in the energy sector is a crucial climate change adaptive strategy. This hypothesis is based on the mandates for the formulation of a SADC climate change action plan and for mitigation in the energy sector. These mandates are contained in the texts of the SADC-CNGO Climate Change Agenda, 2012 and the Southern Africa Sub - Regional Framework on Climate Change, 2010 respectively. It is the main aim of this paper to investigate recent developments in the formulation of harmonised SADC law and policy on climate change in general and law and policy pertaining to mitigation in the energy sector specifically. In achieving the stated aim, themes to be investigated by means of a literature study are those of energy-related greenhouse gas emissions and global climate change and harmonised sub-regional policy on mitigation in the energy sector as adaptive measure in the SADC <![CDATA[<b>Considerations for a sustainable hybrid mini-grid system: A case for Wanale village, Uganda</b>]]> The extension of modern energy services to rural sub-Saharan Africa has continuously provided a challenge to energy utilities. The continued reliance on diesel generators for rural electrification is increasingly becoming unsustainable, due to a number of factors, among which includes their high fuel dependency, and the uncertainty surrounding the price and availability of fossil fuels. While the influx of renewable energy technologies has provided a means for providing off-grid electrification services, the intermittent nature of renewable resources poses a challenge, as energy generation does not always coincide with usage. Through a combination of renewable energy technologies, energy storage, and conventional diesel generation, a hybrid mini-grid system is able to achieve synergy in operation, hence providing a reliable means of extending electricity services to rural consumers. In this paper, a hybrid mini-grid system is proposed for the supply of electricity to a remote village in Uganda. Renewable energy resources are identified, an estimation of the projected village short-term electricity demand is modelled, and using HOMER software, a hybrid mini-grid system is designed, components sized, and the system optimized for efficient and reliable operation to meet the village demand at an affordable cost. A well designed and operated hybrid mini-grid system offers a viable tool for the electrification of even the remotest of areas <![CDATA[<b>Numerical simulation of atmospheric boundary layer and wakes of horizontal-axis wind turbines</b>]]> Simulations of wind turbine wakes are presented in this paper using the three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations employing the k-ε turbulence model appropriately modified for the atmospheric flows. The actuator disk approach is used to model the action of the turbine rotor. Modified formulations of the inlet conditions and the wall functions are used to allow consistency between the fully developed atmospheric boundary layer (ABL) inlet profiles and the wall function formulation. Results are presented and compared with three wind turbines running under neutral atmospheric conditions. The results demonstrate that the accurate simulation of the atmospheric boundary layer applying enhanced inlet conditions and wall function formulation consistent with the k-ε model can give very useful information about the wakes, directly contributing to the accurate estimation of the power of the downstream turbines <![CDATA[<b>Solar water heater contribution to energy savings in higher education institutions: Impact analysis</b>]]> This paper focuses on the impact of Solar Water Heaters (SWH) at a higher institution of learning. An energy audit was conducted for the evaluation of the energy conservation measure: energy conoduction Energy is a key element in the development of any country or institution; as a result any shortage in energy will have a serious effect on the economy and social aspect of such country or institution. South Africa has, in recent years, experienced high economic growth as well as a rapid expansion in the elsumption analysis, correlation of consumption with weather; financial criteria, payback period and needed solar heater system (SWH) to determine the energy that may be termed as wastage or can be saved. The method of investigation includes assessment of the hot water usage within the institution campus and residencies, analysis of bills, metering and development of a software model for the analysis of energy use, system needed and environmental variables. This renewable measure (SWH) showed a high potential of energy and financial savings for higher education institutions especially those with residences